The present invention is directed to compositions and methods of treating cancer by gene therapy using a therapeutic gene, such as a tumor suppressor gene delivered by a gene delivery system, such as a recombinant viral vector delivery system, formulated in a buffer comprising a delivery-enhancing agent. One embodiment of this invention relates to the delivery of a tumor suppressor gene (e.g., p53 or retinoblastoma (RB)) to cancerous epithelial tissues and organs, such as the bladder, using a recombinant adenoviral vector delivery system formulated in a buffer comprising a delivery-enhancing agent.
Carcinoma of the bladder represents a significant source of morbidity and mortality. Bladder cancer ranks 10th in males and 12th in females in cancer related mortality (Cancer Facts and Figures, Amer.Can.Soc. 5:11 (1995)). Therapies available for the treatment of bladder cancer include adjuvant chemotherapy or immunotherapy, transurethral resection of superficial disease, radical cystectomy or radiotherapy which is often combined with systemic chemotherapy. Despite these therapeutic options, overall survival has not changed appreciably. (Ibid) Thus, new therapeutic modalities must be developed for the treatment of bladder cancer.
Gene therapy strategies have been developed as an alternative therapeutic approach (See for example, Brewster et al. Eur Urol 25:177–182 (1994); Takahashi et al., Proc Natl Acad Sci USA 88: 5257–5261 (1991); Rosenberg, S A, J. Clin Oncol. 10:180–199 (1992)).
Distinct approaches have been developed to treat neoplasms based on gene transfer methods. Methods have been developed to correct specific lesions at defined genetic loci which give rise to neoplastic transformation and progression (Spandidos et al., Anticancer Res. 10:1543–1554(1990); Banerjee et al. Cancer Res. 52:6297–6304 (1992)). Overexpression of dominant oncogenes may be addressed using techniques to inhibit the transforming gene or gene product. Loss of tumor suppressor gene function may be approached using methods to reconstitute wild-type tumor suppressor gene function (Goodrich et al., Cancer Res. 52:1968–1973 (1992)). Besides these methods to achieve mutation compensation, genetic techniques have been developed to specifically and selectively eradicate tumor cells. These approaches of molecular chemotherapy rely on specific expression of toxin genes in neoplastic cells (Abe et al., Proc Soc Exp Biol Med. 203:354–359 (1993)). Finally, gene transfer methods have been used to achieve antitumor immunization. These methods of genetic immunopotentiation use techniques of genetic immunoregulation to enhance immune recognition of tumors. Consequently, a variety of distinct approaches have been developed to accomplish gene therapy of cancer.
A high incidence of mutations has been observed in tumor suppressor genes, such as p53 and RB, in the case of carcinoma of the bladder (Fujimoto et al. Cancer Res. 52:1393–1398 (1992); Cairns et al. Oncogene 6:2305–2309 (1991)). For such genetic lesions of tumor suppressor genes, reversion of the neoplastic phenotype can be demonstrated with replacement of the corresponding wild-type tumor suppressor gene (Spandidos, Id.; Banerjee, Id.).
In vitro studies using cell lines derived from human bladder tissues have demonstrated efficient transgene expression following infection with recombinant adenovirus (Bass et al. Cancer Gene Therapy 2:2:97–104 (1995)). Experiments in vivo have also shown adenovirus transgene expression in the urinary bladder of rodents after intravesical administration (Ibid; Morris et al. J. Urology. 152:506–50(1994)). In vitro experiments with wild-type adenovirus demonstrate that virus attachment and internalization is not influenced by benzyl alcohol, but do demonstrate an enhanced uncoating of the virion (Blixt et al. Arch. Virol. 129:265–277 (1993)). In vivo efforts with agents (e.g. acetone, DMSO, protamine sulfate) can break down the protective “mucin” layer that protects the bladder epithelium from bacteria, viruses and other pathogens (Monson et al. J. Urol. 145:842–845 (1992); Parsons et al. J. Urol. 143:139–142 (1990)). None of the methods tried to date achieve enhanced delivery of a therapeutic tumor suppressor gene to the bladder for the treatment of bladder cancer. In order to accomplish gene therapy for treatment of bladder cancer, gene therapy methods must be developed to accomplish direct, optimal, in vivo tumor suppressor gene delivery to the bladder epithelium.
These needs and others are addressed by the instant invention.